Here I have a spare x86 board which has a low energe costing AMD CPU built on it. I am planning to DIY a home use file server with it running a Debian base system and some common service programs such as ftp/telnet/svn/samba... etc.
The main storage media is a 4GB EIDE flash disk, with possibility to mount USB HDDs. The board can support up to 1GB of RAM. The rough idea is to install Debian on the 4GB flash disk, and using external USB HDDs as data storage.
Since the flash disk has a limited number of erase cycles, I would like to avoid data writing to it as much as possible. The Linux swap partition, among other things, is to be disabled.

My questions are:

What are the other possible ways in which my system would write data to the flash disk at run time, and how to avoid them?
For one thing whether linux persists log messages to hard disk?